Telephone-exchange system



1. L. WRIGHT. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR. 3, 1916.

'1 39,010, Patented May 4, 1920.

7 SHEETS-SHEET I.

.YMZIW J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED MR. 3, 191a.

Patented May 4, 1920-.

1. L WRIQHT. TELEPHONE EXCHANGE SYSTEM.

APPLI CATION FILED MAR- 3. 1916.

Nwm A P.

J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR. a. l9l6.

1,339,010. Patented May 4,1920.

7 SHEETS-SHEET 4.

: ywmaw J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR-3,19%.

Patented May 4,1920.

7 SHEETS-SHEET 5.

; FIH

J. L. WRIGHT. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR- 3. 1916-,

Patented May 4, 1920..

7 SHE S-SHEET 6.

' J. L. WRIGHT.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR. 3. 1916.

Patented May 4, 1920.

7 SHEETSSHEET Z.

UNITED STATES PATENT OFFICE.

JOSEPH L. WRIGHT, OF CLEVELAND, OHIO, ASSTGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Application filed March 3, 1916. Serial No. 81,851.

To all whom it may concern Be it known that I, JOSEPH L. lVnioH'r, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Telephone-EX- change Systems, of which the following is a specification.

My invention relates to telephone exchange systems, and has for its object improvements of such systems wherein auto matic switching mechanism is employed for interconnecting telephone lines.

Thepresent invention is in the nature of an improvement over the system disclosed in Letters Patent No. 1,137,372, granted to me April 27, 1915.

In the present instance when calls are originated over the telephone lines they are automatically transferred to an idle operator, who thereafter by means of switching mechanism and control devices extends the calls to their proper destinations.

The switching'mechanism under control. of the operator comprises what are ordinarily termed first selector, second selector and connector switches. Vith my invention these switches are not driven predeterminedly in order to effect the proper connections with lines or trunks. Each switch is entirely self-controlled by its 'own'inotive power. These switches in addition to being provided with the usual movable wipers to engage cooperating contacts are provided with what may be termed designating wipers and contacts. These designating contacts are arranged in certain order and connected with corresponding contacts of the keyboards at each operators position.

Each operator is provided with a keyboard similar to that of an adding machine. Each key-board is provided with a number of rows of keys or buttons each row consisting of ten buttons. The number of rows is determined by the number of switches in a series, under control of the operator to establish a connection from the line of the calling subscriber to the line of the called subscriber. One row of buttons is provided for each selector switch while two rows of buttons are provided for the connector switch of the series.

In the present instance I have shown my invention as applied to an exchange of tenthousand line capacity wherein first selector, second selector and connector switches are employed. I

A novel feature of the present invention consists of the manner of controlling the order in which the various rows-of buttons are placed in association with the respective switches which they are to control. The ordinary step-by-step or power driven switch which may be termed a sequence switch is dispensed with.

Each row of buttons is placed in association" with the switch it is to control and when this switch selects or engages the designated contact, the depressed button in the row is automatically restored and the next row of buttons placed in association with the switch it is to control. This sequence of operations is continued until the last switch in the series is operated and all of the buttons restored. The restoration of the button in the last row causes the key-board to be automatically disconnected from the switches used in building up the connection from the calling to the called subscribers line.

With this arrangement the progress of a call can be noted and any failure of a button to restore will indicate that a certain switch has not operated properly and the attendant in charge of the exchange can then quickly locate such a switch.

My invention is illustrated in the accompanying drawings, wherein:

Figure 1 shows a subscribers line and control circuit.

Fig. 2 shows a primary and first selector switch. circuit.

Fig. 8' shows a second selector switch circuit.

Fig. 4 shows a connector switch circuit.

Fig. 5 shows a secondary or key-set switch control circuit.

Fig. 6 shows the circuit of the secondary or keyset switch.

Fig. 7 shows the operators controlling device.

Referring to Fig. 1, the subscribers station A is equipped with apparatus usual in common battery systems and the line wires from this station terminate at the central ofiice in a line relay 2. The line relays are divided into groups, there being ten groups to each one-hundred lines. The wlndings of each group of ten relays are common to the winding of a group relay 3 so that when any line relay is energized, the group relay associated with it is also energized. The group relay when operated makes the row contact in the primary switch busy, while the line relay when operated makes the individual test contact in the primary switch busy.

The switch W is common to a group of one-hundred lines and is made to rotate whenever a call is originated. In rotating this switch picks out an idle primary switch and starts the same hunting for the calling line.

Referring now to Fig. 2, the primary switch is shown at C. On the spindle of the switch is mounted a row wiper 64 which passes over the row contacts when the switch rotates. This switch first rotates to pick out the group of calling lines and then steps vertically until the calling line is found.

The first selector switch is shown at D and is similar to the primary switch. The spindle of this switch carries a set of row wipers which engage row contacts when the switch is rotating and also another set of wipers which engage the vertical rows of contacts after the switch finds the proper row contact.

All of the primary, first selector and connector switches are provided with two distinct kinds of wipers. namely. row wipers to pick out the group while the switch rotates and vertical wipers which pick out contacts in the vertical rows. The row wipers of the selector and connector switches in passing over the contacts cause certain circuit combinations in relation to the operators keyboard or controlling device.

Referring again to Fig. 2, the wipers 63 of the primary switch C and the wipers 56 of the first selector switch D are joined as indicated. by the heavy lines for conversational purposes. The tip and sleeve conductors are separated by the condensers 43 and 4-4;. Relay 23 and the retardation coil 26 supply talking current to the calling subscriber. Relay 21 is the starting relay of the primary switch and corresponds to the line relay 2, (Fig. 1) as it controls the action of the operatofis key-set switch (F ig. 6). Relay 22 is the row test relay while 24 is the individual test relay. Relay is operated when. the key-set switch picks out the trunk and remains energized while the various switches are being controlled and until the connection between the calling and the called subscriber is established. Relay 27 is the test relay oi the first selector switch and remains energized while the test wipers are passing over busy contacts. Re-

lay 28 is energized whenever either the rotary or vertical magnets of the primary switch are operated and also when the vertical and rotary magnets oi" the first selector switch are operated. The circuits of these magnets are normally completed through the back contacts of this relay 28, and so therefore whenever it is actuated the magnet circuits are broken. The action thus set up between the relay and the magnets causes the latter to vibrate and continue to do so until their energizing circuits are opened.

The controlling relay 81 is connected to the row wiper as shown, and when the proper circuit combination is formed between the key-board and the contacts which this wiper passes over closes the circuit of the testing relay 2?. The action of this latter relay disconnects the rotary magnet of the first selector switch and in its place connects the vertical magnet. At the first vertical step of the first selector switch the controlling relay 81 is disconnected from the tip conductor of the trunk.

Referring now to Fig. 3, the second selector switch at E is similar to that of the first selector switch and is controlled in the same manner. The control relay 84 is connected to the row wiper and when operated the circuit of the rotary magnet is disconnected and the vertical magnet connected in its place.

Referring'now to Fig. 4, the connector switch at Gr is provided with a set of wipers leading to the talking conductors oi the called line and a test wiper 360 which is also a part of the circuit of the cut oil" relay. This switch besides having the row wiper 375 also has a wiper 865. This latter wiper is connected to the row wiper and also to the control relay 310. In the connector switch it is necessary to pick out a predetermined individual contact in the vertical row as well as to pick out a predetermined row contact, thus necessitating the additional wiper 365.

Relay 815 is operated at the first action of relay 305 and connects or closes the circuit ofthe rotary magnet causing the connector switch to rotate. l/V hen the control relay 310 operates after the switch has rotated, the circuit of the relay 320 is closed, thereby disconnecting the rotary magnet and in its place connecting the vertical magnet. The switch new steps vertically until the wiper closes the circuit of the control relay 310. When such a circuit is closed. this relay acting will close the circuit of relay 825, thereby disconnecting the vertical magnet and causing the wipers oi the connector switch to rest on the contacts of the called line. This last action of the control relay 310 connects the test relay 345 to the test wiper 360. If the called line is busy, the action of this relay will close the circuit of the release magnet 385 and restore the switch and also place a suitable busy tone signal to the calling subscriber.

If the called line is not busy then the re lay 330 will be placed in series with the cutoff relay. The action of relay 330 disconnects the control relay and closes the tip and sleeve conductors of the trunk. Relay 850 is the ringing relay and is operated intermittently by means of the commutator 500 until the called party answers, whereupon this relay is disconnected. Relay 335 and retardation coil 3 10 supply talking current to the called subscriber.

When the called subscriber answers he controls the action of the connector switch, while the calling subscriber controls the action of the primary, first and second selector switches.

Referring to Fig. 5, the switch shown at Y corresponds to the switch 1 of Fig. 1 and serves to pick out an idle secondary switch.

Referring to Fig. 6, the secondary switch is shown. The switch M is similar to and acts in the same manner as the primary switch C of Fig. 2. The wipers 16-7 connect with the tip and sleeve conductors of the primary trunk in Fig. 2 over which the operator converses with the calling subscriber and over which the action of the various selector and connector switches are controlled. 168 is the row wiper and scrvesto pick out the particular group of trunks in which the calling primary trunk is located. 154 is the individual test relay for selecting the individual calling primary trunk in the group. Relay 156 is the signal relay and operates in series with relay 25 of Fig. 2. Relay 152 is the starting relay and corresponds to relay 21 and relay 153 is the row test relay. 155 is the relay operated when the answering button 248 is depressed and serves to connect the operators telephone set across the tip and sleeve conductors of the trunk. 157 is the starting relay and operated when the ararting button 241-7 is depressed.

The operators key-board shown in Fig. 7 comprises four rows of buttons, each row being equipped with ten buttons. These buttons are of the usual locking and indicating type and so arranged that when a button in a particular row is depressed a common latch bar will be operated thereby releasing the button formerly depressed. Each row of buttons of which there are four is provided with a release magnet. These magnets serve to operate the common latch bar of its row when energized. These magnets designated as 721, 722. 7 23 and 72% are each controlled by their respective relays 711. 712. 713 and 71 1. Each one of these relays as shown is common to a particular row of buttons. Each row of buttons is also provided with a set of master contacts operated by the latch bar when a button in the row is depressed. The connections from these master springs of each row are in series relation. When a button in each of the four rows is depressed the connection extending to the first row of buttons is connected to conductor 750. This conductor 7 50 is connected in proper sequence to the various rows of buttons R, S, T and U. The connection to each row of buttons includes the winding of their respective relays 711, 712, 713 and 714:.

v The designating contacts of the selector and connector switches are connected in multiple, that is to say No. 1 contacts of each switch are connected in multiple,No. 2 contacts connected in multiple. and likewise the remaining contacts connected in multiple. Each set of contacts is connected respectively to one terminal. of a separate source of battery supply indicated at 7 01 to 710 inclusive. Opposite terminals of these various batteries are connected. respectively to corresponding contacts in the rows of buttons.

With this arrangement combinations are set up between the key-board and the switches whereby the latter are caused to come to rest on contacts corresponding to the buttons depressed on the key-board.

In case No. 1 button in the first row is depressed and the first selector switch which is controlled by the first row R is set in motion the circuit of relay 711 will be completed when the designating wiper of the first selector switch engages No. 1 designating contact such as 7 11. '7

The operation of my system is as follows:

The subscriber at A upon removing his receiver closes the circuit of the line relay 2 in series with the group relay 3. This latter relay operating closes the circuit of relay 41 in which in turn connects ground to one terminal of the relay 5 and also closes the circuit of the stepping magnet 7. The stepping magnet operating closes the circuit of relay 6 which in turn opens the circuit of the magnet itself causing it to vibrate and step the switch W. This switch will continue to rotate until an idle primary switch such as shown in Fig. 2 is found. As soon as such a switch is found. the relay 5 is placed in series with relay 21 (Fig. 2)

tion of magnet 31 causes the switch C to operate until the wiper 64 reaches the bus row contact.

The wiper 64 is carried on the same spindle with the wipers 63 and 65, and while the switch is rotating the wiper 64 passes over contacts leading to the group relay 3.

As there are ten of these group relays to each one-hundred lines it follows that the wiper 64 in rotating to its extreme position will pass over ten contacts.

There are ten sets of individual contacts arranged in vertical rows associated with each row contact and which the wipers 63 and 65 respectively engage. It follows therefore that after the switch picks out the group in which a line is calling, it will afterward step verticallv until the wipers engage the contacts of the calling line.

As soon the row contact is found, the circuit of relay 22 is closed as follows: battery B, 80, back contact of relay 24, 71., 22, 64, 13, contact of relay 3, to ground. The relay 22 in operating disconnects the rotary magnet 31 and in its place connects the vertical magnet 30, thereby causing the switch to step vertically until the busy individual test contact is found. As soon as such a contact is found the circuit of relay 24 is closed as follows :battery B, 24, 68, contacts of relay 22, 67, 11, contacts of relay 2 to ground through the contacts of relay 1. Relay 24 operating opens the wire 71 and disconnects relay 22 which in falling back disconnects relay 24 from the wire 67 and connects it instead to wire 66, thereby placing relays 24 and 1 in series.

The operating of relay 1 disconnects the line relay 2 and the group relay Relay 24 connects battery to the windings of relays 23 and 25 and the falling back of relay 22 connects ground to the coil 26, thereby supplying the calling subscriber with talking current.

Relay 21 remains energized until the primary switch finds the calling line and until the key-set switch finds the trunk. Relay 21 when first actuated, places battery on the wire 79 to relay 130 and also places battery to wire 62 which is connected to the individual test contact of the key-set switch (Fig. 7).

Relay 130 closes the circuit of the stepping magnet of the switch Y through the normally closed contacts of relays 131, 132. The magnet in operating closes the circuit of the interrupter relay 134, thereby cans ing the magnet to vibrate and the swit h to rotate until an idle key-set switch is found. When such a switch is found as shown in Fig. 6, relay 131 is placed in series with relay 152 by the following path: ground, contacts of relay 130, 131, 138, Y, 140, 152, 195, 196, 197 to battery 13 through the operators jack 400. Relay 131 operating places battery on wire 136 to relay 132. As soon as this latter relay operates ground is placed on the wire 13S, thereby shunting relay 131. This direct ground placed on wire 138 makes the wire 140 which is multipled to other Y switches busy. The operating oil relay 132 also places ground on the row wiper or the key-set switch by the following path: ground 139, Y, 141, to the row contact.

The operation of relay 152 connects ground to the rotary magnet 165 through the back contact of relay 153 causing the switch M to rotate. This switch will rotate until the busy row contact is found, whereupon the circuit of relay 153 will be closed as follows: battery 13, contacts of relay 152, 176, 153, 171, 168, 141, 139, contacts of relay 132 to ground. The key-set switch M operates in the same manner as the primary switch 0 (Fig. 2). Relay 153 disconnects the rotary magnet 165 and connects in its place the vertical magnet 164, thereby causing the switch to step. vertically until the busy individual test contact is found.

The finding of this contact closes the circuit of relay 154 as follows: ground, 154, 172, 62, 80, contacts of relay 21 to battery B. Relay 154 disconnects relay 152, thereby cutting off the vertical magnet and causing the key-set switch to rest on contacts leading to the calling primary trunk. Relay 152 becoming deenergized opens the circuit of relay 153 and this latter relay in falling back places relays 156 and 25 in series by the following path: ground, back contact of relay 714, back contact of relay 153, 175,

back contact of relay 157, 202, contact of relay 155, winding of relay 156, 193, 169, 59,

25 to battery B through the contacts of relay 24. The operating of relay 25 (Fig. 2) disconnects relay 21 and also relay 5 (Fig. 1). The releasing of relay 5 frees the switch WV allowing it to pick out other primary switches. Relay 156 operating places battery on wire 181 causing the lamp 243 to light.

s soon as relay 21 in Fig. 2 became disconnected battery was removed from the individual test contact of the key-set switch, thereby allowing relay 154 to fall back. Relay 21 also releases relay 130, thereby restoring relay 132 so as to allow the switch Y to be used by other trunks in picking out key-set switches.

In the present system I have provided ten primary switches as shown in Fig. 2, for each one-hundred lines. Each group of ten primary switches is in turn provided with one Y switch for picking out idle key-set switches. The percentage and grouping of the trunks and lines can be varied to suit trafiic conditions.

The wire 141 leading from the Y Switch to the row contacts of the key-set switch is not multipled. The Y switch picks out an idle key-set switch and then places ground on the row contact of the selected switch and these row contac s are not multipled. This arrangement prevents interference be-' tween other Y switches and also between the key-set switches. In no case is ground placed on more than one row contact of any key-set switch at the same time.

In Fig. 1 the switch W is individual to one hundred lines and picks out a group of primary switches, and in this case the row contacts of a group of primary switches are multipled.

The lighting of the lamp 243 notifies the operator of a call, and she then presses button 248 operating relay 155. The operation of this relay connects her telephone set across the trunk wires, disconnects relay 156, thereby extinguishing lamp 243. The disconnecting of relay 156 also opens the circuit of? relay 25 (Fig. 2), which in falling back closes the tip and sleeve conductors of the trunk, allowing the operator to converse with the calling subscriber.

The operator upon receiving the number desired, which 1 will assume to be 1470, sets up this number on the keyboard in the following manner: She presses No. 1 button in the thousands row ll, No. 4 button in the hundreds row 8, No. 7 button in the tens row T and No. 10 button in the units row U. After setting up these buttons she depresses the starting button 247 thereby completing the circuit of relay 157 by the following path: ground, contacts of button 247, 186, winding of relay 157, 193, 169, 59, winding of relay 25, contacts of relay 24 to battery B.

T he operation of relay 157 disconnects relay 155 and connects coil 158 to the sleeve conductor 151. and also connects the wind ing of relay 711 to the tip conductor 150. Winding of coil 158 is placed in series with the winding of relay 29 by the following path: ground, winding of coil 158, contacts of relay 157, 151, 167, 61, contacts of relay 27, 53, cam springs 41, 36, winding of relay 29, contacts of relay 25 to battery B. The operation ot relay 29 completes the circuit ot the rotary magnet by the followinn; path: battery B, contacts of relay 28, 71, contacts of relay 29, contacts of relay 27, cam springs 40, winding of magnet 34 to ground. The operation of the magnet completes the circuit of the vibrating relay 28 which in turn opens the circuit of the magnet 34. Due to the interruptions set up between the magnet and the relay the first selector switch will rotate until the desighatingwiper 48 engages the first contact whereupon relays 81 and 711 will be placed in series by the following path: battery 701, designating contact 741, wiper 48, winding of relay 81, G0. wiper 167, 150, contacts of relay 157, 750, master springs 7 31, winding of relay 711, contacts of No. 1 button in the row ll to the opposite side of battery 701.

The operation of relay 81 completes the circuit of relay 27 and the operation of this latter relay disconnects the rotary magnet series with the winding of magnet 32. This ground connection is connected to the looking contact of relay 27 through the contacts of relay 28. While the switch is stepping vertically due to the action of magnet 33 and the vibrating relay 28, the circuit of relay 27 is maintained as long as the test wiper 57 passes over busy or grounded contacts.

As soon as an idle contact is found and while relay 28 is energized the circuit of relay 27 is unguarded and it restores thereby causing the wipers to engage contacts leading to an idle second selector switch.

The operation of relay 711 completes the circuit of the release magnet 721 thereby causing the latch bar to be operated, thus restoring No. 1 button to its normal position. The restoration of the latch and button also causes the master springs 731 to assume the position shown in Fig. 7. As the master springs of the other three rows of buttons are operated then the connection from row oi buttons 8 is extended through the winding of relay 712 to conductor 750.

lVhile the first selector switch is stepping vertically the tip and sleeve conductors, due to the operation of relay 27, are severed. thus rendering it impossible for the operation of relay 712 during this time.

After the selection of? the second selector switch, such as shown in Fig. 3, ground is connected to the test conductor leading to the winding of relay 81 thereby causing its operation. The operation of this relay completes the circuit of the rotary magnet 87 the following); path: battery contacts of relay 81, contacts of relay 83, 94, cam springs 106, 99, winding of magnet 87, 100, contacts of the vibrating relay 82 to ground. The operation of the magnet 87 and the vibrating relay 82 causes the switch to rotate. When the designated wiper 103 engages the fourth contact, the winding of relays 84 and 712 are placed in series by the Following path: battery 704, designating contact 744, wiper 103, 97 winding of relay 84, 90, wiper 56, 54, 60, 167, 150, contacts of relay 157, 750, master springs 731, 732, winding of relay 712, No. 4 button in the row S to the opposite side of battery 704.

The operation of relay 84 completes the the circuit of the magnet 83 thereby disconnecting the rotary magnet 87 and 1n lts place connecting the vertical magnet 88.

Due to the vibrating elfect set up between I the vertical. magnet 88 and the relay 82 the second selector switch will step vertically until the test wiper 102 engages contacts extending to an idle connector switch. As soon as such a switch is selected relay 83 restores thereby closing the tip and sleeve conductors which were formerly severed at its operation.

The operation of relay 712 completes the circuit of magnet 722 which thereupon opcrates the latch bar restoring No. 4L button in the row S and restoring the master springs 732 to normal position. The restoration of these springs places the connection extending to the buttons of the row T to conductor 750 and includes the winding of relay 713.

After the selection of an idle connector switch such as shown in Fig. 4, the winding of the coil 158 is placed in series with the winding of relay 305 over the sleeve conductor. The operation of relay 305 completesthe circuit of relay 315 by the following path: battery B, contacts of relay 305, 309, winding of relay 315, 308, 102, 93, contacts of relay 82 to ground. The operation of relay 315 completes the circuit of the rotary magnet 390 by the following path: battery B, contacts of relay 325, 333, con tacts of relay 315, contacts of relay 320, 318, winding of magnet 390, contacts of vibrating relay 685 to ground. The operation of the magnet 390 completes the circuit of relay 685 which upon operating disconnects ground from the Winding of the magnet. The action set up between the magnet and the relay causes the connector switch to rotate until the designating wiper 375 engages the seventh contact. As soon as this contact is engaged relays 713 and 310 are placed in series over the tip conductor. The relay 713 has one terminal connected to bat tery 707 through the contacts of No. 7 button in the row T. Relay 310 has one terminal of its Winding connected to the opposite side 'of this battery 707 due to the wiper 37 5 engaging contact 747. The op eration of relay 713 completes the circuit of the release'm'agnet 723 thereby causing the restoration of No. 7 button in the row T and at the same time the master springs 733 are returned to-th'eir normal position thereby causing the winding of relay 714 to form the connecting link between therow of but tons U and the common conductor 750.

The operation 'of relay 310 completes the circuit of relay 320 by the following path: battery B, contacts of relay 31 0, 324, cam springs'398, winding of relay 320 to ground connected to the test conductor through the contacts of relay 82, Fig. 3.. The operation of relay 320 disconnects the rotary magnet 390 and in its place connects the vertical magnet 395. The operation of the vertical magnet completes the circuit of the vibrating relay 685 and the action set up between the relay and the magnet causes the connector switch to step vertically.

At the first rotary step of the connector switch the cam springs 800 were operated thereby disconnecting battery from the winding of relay 305.

The connector switch will step vertically until. the designating wiper 37 5 engages the tenth contact connected to one terminal of battery 710. The opposite terminal of this battery is connected to one terminal of re lay 71 1 through the contacts of No. 10 button in the row U. The other terminal of each of these relays is connected over the tip conductor oi the trunk thereby causing their operation. The operation of relay 310 at this time completes the circuit of relay 325 by the following path: battery B, con tacts of relay 310, 2324, cam springs 398, 316, winding 0'! relay to ground through the test wire 308. The operation of relay removes battery supply from the winding of the vertical magnet 395 thereby causing the connector switch to come to rest with the wipers 355 and 360 engagin contacts of the wanted or called line. The operation of relay 310 also connects the winding of the test relay 3.4.5 to the test wiper 360 and in case the called line is busy relay 3 15 will be operated and complete the circuit of the re lease magnet 385, thereby causing the restoration o the connector switch. The operatiiin oi relay 3 1-5 under these conditions will also connect a suitable busy'tone test to one of the conductors extending to the call ing subscribefis line notifying him that the called-tor line is busy. I

In case the called-tor line is not busy, re lay 34-5 will not be affected and after relay 310 restores relay 330 is placed in series with the cut-off relay of the called line through the test wiper 360. i

The operation of relay 330 closes the tip and sleeve conductors of the trunk, connects battery to the winding of relay and connects ground to the winding of the retardation coil 3 b). The operation of relay 330 also completes the circuit or. the ringing relay 350 by the following path: ground, connnutator 500, winding of relay 350, 331, contacts of relay 325, contacts of relay 330 to battery B. The relay 350 is operated inttu-mittently by means of the commutator 500 and when in its energized condition applies generator 356 to the line of the called subscriber.

lVhen. the called. subscriber answers during a non-ringing period the tip relay 335 is energized. The operation of this relay removes battery from the locking contacts of relays 320 and 315 thereby causing their restoration. The restoration of relay 320 in turn. removes battery from the locking contact of relay 325 causing its restoration. The operation of relay 330 also disconnects the windings of relay 305 and 3.10 from the sleeve and tip conductors respectively.

IV hen relay 31.0 was operated the second time, relay 71st (Fig. 7) was operated also. The operation of this latter relay completes the circuit of the release magnet 72% thereby causing the restoration of No. 10 button in the row U and also causes the restoration oi"? the master springs 784-. The operation of relay 71% also completes the circuit of relay 166 of the switch M by connecting ground to its winding. Relay 714 also removes ground from the locking contact of relay 157 causing its restoration as well as the restoration oi. relay 25 (Fig. 2). The operation of magnet 166 causes the switch H to restore thereby disconnecting the operators control device from the primary trunk.

It will be noted by referring to Fig. 7 that the restoration of the button in the last row and the restoration of the master springs 734 leaves the common conductor 750 free from any connection.

After the parties are through talking, the ailed subscriber, upon hanging up his receiver causes the relay 335 to fall back and close the circuit of the release magnet 385 as follows: battery B, contacts of relay 335, 314. contacts of relay 315, 385, 322, cam springs 397 to ground. The action of this release magnet restores the switch G to its normal position.

The calling subscriber upon hanging up his receiver causes the tip relay 23 (Fig. 2) to fall back, thereby closing the circuit of the release magnet 32 as follows: battery B, can] springs 38, 73. contacts of relay 23, 58, contacts of relay 28. 72, 32, 75, cam springs l-l to ground. The operation of this magnet causes the switch (l to return to its normal position opening the cam springs 38, thereby removing battery 13 from the wire 73 allowing the circuit of the release magnet 35 of the switch D to become energized over the tollowing path: battery B, 73, contacts of relay 23. 58, contacts of relay 28, 72, 32, 75 to ground through the cam springs 41. The operation of relay 35 restores the switch I), thereby opening the cam springs 41 and disconnecting the energizing circuit for the release magnets. As soon as the test wiper 57 of the first selector switch leaves the test contact, then the relay 81 (Fig. 3) falls back and closes the circuit of the release gnet 86 as follows: battery B, contacts of relay 81, S6, 89, cam springs 95 to ground. The operation of this magnet causes the switch It to restore and open the release cir cuit.

In case the called party does not answer, then the calling party has complete control of all the switches and releases the primary, first and second selectors in the manner just described. The releasing of the second selector switch (rig. 3) removes ground from the test wire 308, disconnects all three relays 315, 320 and 325, thereby closing the circuit of the release magnet 385 just as though the called subscriber had answered and then hung up his receiver.

Having thus described my invention what I desire to secure by Letters Patent is:

1. In a telephone exchange system, the combination with automatic switches for interconnecting subscribers lines, of a keyboard. comprising a plurality of rows of buttons for controlling the operation of said. switches, certain rows of said buttons being allotted to certain of said switches, restoring means for each row of buttons, means controlled. by each of said switches after performing its functions for rendering operable the restoring means of its allotted row of buttons.

2. In a telephone exchange system, the combination with automatic switches for interconnecting subscribers lines, of a keyboard comprising a plurality of rows of depressible buttons for controlling the operation of said switches, certain rows of buttons being allotted to certain of said switches. restoring means for each of said rows of buttons, means controlled by each of said switches when it assumes a position corresponding to a button depressed in. its allotted row to render operable the restoring means for said row.

3. In a telephone exchange system, the combination with a series of automatic switches. of key-board comprising a plurality of rows of buttons for controlling the operation of said switches, certain rows of said buttons adapted to be allotted to cer tain of said switches, means controlled by said switches in their operation to cause the proper allotment of said buttons.

4.. In a telephone exchange system, the combination with av series of progressively operated switches. of a key-board comprising a plurality of rows of buttons for con trolling the operation of said switches. certain rows of said buttons adapted to be allottcd to certain of said switches, restoring means for each row of said buttons, the allotment of said buttons being controlled by the operation of the restoring means, the

storing means for each of said rows of buttons, means controlled by said switches in their progressive operation for rendering said restoring means operable.

6. In a telephone exchange system, the combination with a series of progressively operated switches, of a key-board comprising a plurality of rows of buttons for controlling the operation of said switches, certain rows of said buttons adapted to be allotted to certain of said switches, restoring means for each of said rows of buttons, the restoring moans of each. row being rendered operable by the progressive operation of their respective switches, the operation of the restoring means serving to cause the proper allotment of said buttons among said switches.

7. In a telephone exchange system, the combination with automatic switching mechanism comprising first selector, second selector and connector switches, of a keyboard comprising a plurality of rows of buttons for controlling the operation of said switches in the order named, certain of said rows of buttons adapted to be associated with certain of said switches, restoring means for each of said rows of buttons, means controlled by the first selector switch in its operation to render operable the re storing means of the first row of buttons, the restoring of the first row causing the association of the next row of buttons with the second selector switch, means-controlled by the second selector switch in its operation to render operable the restoring means of the second mentioned row of buttons, the restoring of the second row of said buttons causing the association of another row of buttons with the connector switch. means controlled by the connector switch in its op eration for restoring the last mentioned row of buttons.

8. In a telephone exchange system, the combination with a series of progressively operated switches, of a key-board comprising a plurality of rows of buttons for controlling the operation of said switches, contacts for each of said rows of buttons, restoring means for each of said rows of buttons, means controlled by said switches in their progressive operation for rendering said restoring means operable through the medium of said contacts.

9. In a telephone exchange system, the combination with a series of progressively operated switches, of a key-board compristrolled through said contacts by the progressive operation of said switches.

10. In a telephone exchange system, the combination with a series of progressively operated switches, of a key-board comprising a plurality of rows of buttons for controlling the operation of said switches, a restoring magnet for each of said rows of buttons, means controlled by said switches in their progressive operation for rendering operable said magnets according to the progressive operation of said switches.

11. In a telephone exchange system, the combination with automatic switches for interconnecting subscribers lines, of a keyboard comprising a plurality of rows of buttons for controlling said switches, releasing means individual to each of said rows, an automatic switch for connecting said key-board with said switches, restoring means for said switch, means controlled by the series of switches in their progressive operation to render operable the restoring means of each of said rows, means controlled in the release of the last row of buttons for rendering operable the restoring means of said automatic switch.

12. In a telephone exchange system, the combination with. a plurality of progressively operated switches, a key-board having a plurality of rows of buttons, restoring means individual to each of said rows,

means controlled by said switches in their operation for rendering operable the restoring means of each of said rows in sequence.

13. In a telephone exchange system, the combination with an automaic switch having associated contacts, wiper arms for said switch for engaging said contacts, a row of buttons provided with a release magnet and contacts, the number of contacts of said buttons equal to the number of contacts in said switch, electrical connections extending between the contacts of said buttons and corresponding contacts in said switch, means controlled over said electrical circuits for effecting the operation of said release magnet when the wiper arms engage said switch contacts.

14. In a' telephone exchange system, the combination with an automatic switch having associated contacts, wiper arms for said switch for engaging said contacts, a row of buttons provided with a release magnet, electrical connections extending from said buttons to said contacts, means controlled by the wiper arms for operating said release magnet over said electrical connections.

15. In a telephone exchange system, the combination with a series of automatic switches operated in sequence, of a keyboard comprising a plurality of rows of buttons for controlling the operation of said switches, of a plurality of sources of power associated with said key-board, re-

storing means for each of said rows of but tons, means controlled by the switches in their sequential operation to connect said power sources to affect said restoring means.

16. I11 a telephone exchange system, the combination of a key-board having a plurality of rows of buttons, restoring means individual to each of said rows, a plurality of step-by-step sequentially operated switches, means controlled by said switches for operating said restoring means in sequence.

17. In a telephone exchange system, the combination of a plurality of sequentially operated automatic switches, a key-board comprising a plurality of rows of buttons for controlling the operation of said switches, means individual to each of said rows and controlled by said switches in their operation to cause the proper cooperation of said buttons and said switches, and restoring means for the buttons of each row actuated when the associated switch has been operated.

18. In a telephone exchange system, the combination of an automatic switch, a keyboard comprising a plurality of depressible buttons, contacts associated with said switch, certain of said buttons being alloted to certain of said contacts, restoring means for said buttons, means controlled by said switch when it reaches a contact corresponding to the depressed button for operating said restoring means.

19. In a telephone exchange system, the combination of an automatic switch, a keyboard comprising a plurality of buttons for controlling the operation of said switch, contacts for each of said buttons, restoring means for said buttons, means controlled by said switch in its operation for rendering said restoring means operable through the medium of said contacts.

20. In a telephone exchange system, the combination with an automatic switch, of a key-board comprising a plurality of buttons for controlling the operation of said switch, contacts associated with each of said buttons, contacts associated with said switch, the contacts of said buttons and said switch being connected in certain order, restoring means for said buttons, said restoring means being controlled through the contacts of said switch and buttons by the operation of said switch.

21. In a telephone exchange system, the combination of an automatic switch, a keyboard comprising a plurality of buttons for controlling the operation of said switch, a restoring magnet for said buttons, means controlled by said switch in its operation for rendering operable said restoring magnet.

22. In a telephone exchange system, the

combination of an automatic switch, a keyboard comprising a plurality of buttons for controlling the operation of said switch, releasing means for said buttons, an auxiliary switch for connecting said key-board with said automatic switch, restoring means for said auxiliary switch in its operation to render operable the releasing means of said buttons, and means controlled in the release of said buttons for rendering operable the restoring means of said auxiliary switch.

23. In a telephone exchange system, the combination of an automatic switch having associated contacts, a row of buttons provided with contacts, restoring means for said buttons, the corresponding contacts of said switch and said buttons being provided with an individual source of current supply, means controlled by said source of current for causing the operation of said restoring means when the switch engages its associated contacts.

24. In a telephone exchange system, the combination of a plurality of sequentially operated. automatic switches, a key-board comprising a plurality of rows of buttons for controlling the operation of said switches, certain rows of said buttons being allotted to certain of said switches, a set of contacts indiyidual to each row of buttons, means controlled by said switches in their operation to cause the proper allotment of said buttons and said switches through the medium of said contacts, and restoring means for said buttons operable after each switch has functioned.

25. In a telephone exchange system, the combination of a plurality of sequentially operated automatic switches, a key-board comprising a plurality of rows of buttons for controlling the operation of said switches, a set of contacts individual to each row of buttons, said contacts serving to cause proper cooperation of said buttons and said switches, and sequentially operated means for restoring said buttons.

26. In a telephone exchange system, the combination of a plurality of sequentially operated automatic switches, a row of buttons allotted to certain of said switches, a set of contacts individual to each row of buttons, means controlled by said contacts for associating said switches with their respective rows of buttons, and means for restoring the allotted row of buttons before another switch is operated.

27. In a telephone exchange system, the combination of? a series of progressively operated switches, a key-board comprising a plurality of rows of buttons for controlling the operation of said switches, contacts for each of said rows of buttons having an associated relay, restoring means for said rows of buttons, means controlled by said switches intheir progressive operation for energizing said relay to render said restoring means operable.

28. In a telephone exchange system, the combination of a series of progressively operated switches, a key-board comprising a plurality of rows of buttons for-controlling the operation of said switches, a relay common to each row of buttons, restoring means for said buttonspneans controlled by said switches in their progressive operation for energizing said relays progressively and for efl'ecting the operation of said restoring means,

29. In a telephone exchange system, the combination'of a series of progressively operated switches, a key-board comprising a plurality of rows of buttons for controlling the operation of said switches, a set of contacts common to each row of buttons, a relay for each row of buttons, restoring means for said buttons, means controlled by said switches in-their' progressive operation for energizing said relays in sequence for operating'said restoring means, the operation of said restoringrneans serving to disconnect said relays through the medium of said contacts.

30; In a telephone exchange system the combination of a series ofiprogressively operated switches, a key-board comprising a plurality of rows of buttons for controlling the oporation of said switches, a restoring magnet for each of said rows of buttons, a relay for each of said rows of buttons, means controlled by said switches in their progressive operation for rendering operable said relays according to the progressive operation of said switches, the operation of said relays in turn causing the operation of said restoring magnets.

31. In a telephone exchange system, the combination of an automatic switch, a keyboard comprising a row of buttons for controlling the operation of said switch, a set of contacts individual to each button ofsaid row, said contacts serving to cause the proper cooperation between said buttons and said switch, and means for causing the restoration of said set of contacts when said buttons and'switch have cooperated 32. In a telephone exchange: system, the combination of an automatic switch provided with a set of contacts, a row ofbuttons.

alloted tosaid switch for controlling. the operation thereof, the contacts ofsaid switch being allotted to certain of said buttons, means controlled by said contacts for associating said switch with a certain button.

ofsaid row, and means to restore said button when said switch has been associated therewith In testimony whereof I aflix my signature in thepresence of two witnesses.

JOSEPH L. WRIGHT. WVitnesses:

A. MCCUNE, H. POLATSEK. 

